"How many people know by not using Windows Azure today, they're giving up thousands of dollars of free cloud credits?" Guthrie asked to laughter and applause from the hundreds of developers in attendance at his Tuesday morning keynote at the Microsoft Conference Center.

Prior to that question, Guthrie had asked how many audience members were using Windows Azure (less than 20 percent) and how many had MSDN subscriptions (most).

Guthrie, corporate vice president for Windows Azure at Microsoft, was referring to MSDN benefits that were streamlined and expanded in June.

The Windows Azure Benefits for MSDN subscribers vary by MSDN subscription level. Those with Visual Studio Professional with MSDN get $50 in free Azure usage credits per month, those with Visual Studio Premium with MSDN get $100 in credits, and those with Visual Studio Ultimate with MSDN get $150 in credits. Those monthly figures add up to $750 per year, $1,300 per year and $1,850 per year, respectively.

Not counted in those credits are MSDN subscriber discounts on services that stretch those monthly credits further. Under the benefits program, subscribers receive a 33 percent discount on Windows Virtual Machines and 25 percent discounts on Cloud Services, HDInsight and Reserved Websites. Software covered by the MSDN subscription, with the exception of the Windows client, can also be used on Azure for free, either uploaded as a VHD, remote installed or selected from Microsoft's virtual machine image gallery.

To illustrate the way the benefits could be used for development and testing, Guthrie used the example of a developer with a Premium-level MSDN subscription and $100 in Azure credits, who could run three virtual machines for 16 hours per day or who could use 80 virtual machines for a 20-hour load test. "How many people here have ever spun up 80 servers for a load test?" he asked, getting one raised hand in the audience. "How many of you should have run an 80-server load test?" Guthrie then joked. "If you're an MSDN customer, there's basically no reason not to use Azure in your dev/test."

In an interview after the keynote, Guthrie estimated that 90 percent of MSDN subscribers would be able to cover all of their dev/test costs through the benefits without any additional charges to their company, involvement from their IT department or need for a credit card number.

Asked the best way for developers to start, he said, "Use what you know today. The beauty about Azure is that it works well with what you already have. You don't have to jump in the deep end to begin with. If you just want to host a Web site, it works pretty much the way you're used to. But then you can add on more. You can gracefully add capabilities and features."